---
title: "CVE-2017-7789\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2017-7789?format=md
keywords: index, follow
---

# CVE-2017-7789

Publication date 4 July 2017

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**5.3 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2017-7789?format=md#impact-score)

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## Description

If a server sends two Strict-Transport-Security (STS) headers for a single
connection, they will be rejected as invalid and HTTP Strict Transport
Security (HSTS) will not be enabled for the connection. This vulnerability
affects Firefox < 55.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| firefox | 17.04 zesty | Fixed 55.0.1+build2-0ubuntu0.17.04.2 |
| 16.10 yakkety | Ignored end of life |
| 16.04 LTS xenial | Fixed 55.0.1+build2-0ubuntu0.16.04.2 |
| 14.04 LTS trusty | Fixed 55.0.1+build2-0ubuntu0.14.04.2 |
| mozjs38 | 17.04 zesty | Not affected |
| 16.10 yakkety | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

5.3 · Medium

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | Low |
  | Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 5.3 · Medium |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-7789)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2017-7789)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2017-7789)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2017-7789)

### Related Ubuntu Security Notices (USN)

+ [USN-3391-1](https://usn.ubuntu.com/USN-3391-1)
+ Firefox vulnerabilities
+ 15 August 2017

### Other references

* <https://bugzilla.mozilla.org/show_bug.cgi?id=1074642>
* <https://www.cve.org/CVERecord?id=CVE-2017-7789>